The solenoid of a paintball marker is the physical connection between the electronics and pneumatics. The firing action is precisely timed via electronics whereas the pneumatics comprimise the mechanical mechanism carrying out the firing action. Solenoids are electromagnet-based devices which control a pneumatic valve in the case of Shockers. The valve switches airflow within the marker, simultaneously pressurizing and depressurizing different parts to actuate the firing valve assembly. Every electronic marker uses a solenoid, although there are many differences in some of the valves used in other applications.

Shocker SFT; frame internal view showing solenoid and circuit boards

Shocker NXT; frame internal view showing solenoid and circuit boards

Shocker SFT; solenoid attached to Shocker body underside

Shocker NXT; solenoid attached to Shocker body underside

The Shocker's solenoid is located attached to the underside of the body, within the grip frame.

Solenoid Operation:The purpose of the solenoid is to take in pressurized air and shunt it to one of two possible output ports. This makes the Shocker's solenoid a "four-way" valve, meaning it has two outputs and two exhausts. The output air is delivered to the solenoid inserts, where it leads to the bolt sleeve and forces the bolt in one direction (either forward or back).

Shocker SFT/NXT firing animation (HE bolt is shown)

Four-way solenoid valve animation (Parker K-series solenoid)

Solenoid Types: (Parker vs. Humphrey)Smart Parts used two different types of solenoids throughout the reign of Shockers and Nerves. The two solenoids were made by different companies; originally Shockers used a Parker K4H03 valve, used from 2003-2005. In early 2005, Humphrey released a new solenoid called the CRCB-0045W which was specifically designed to function in a Nerve, but also worked in a Shocker too. Smart Parts used both the Parker and Humphrey solenoids until late 2006, at which point they reverted to using Parker solenoids in most markers. At present, Humphrey valves seem to be easier to source, but there are still replacements for both varieties.

Neither solenoid is necessarially "better" than the other; they both have advantages and disadvantages. There isn't much need to replace your old solenoid with a different one so long as your marker is currently functioning correctly. Swapping out solenoids may lead to a performance increase but it may simply be due to manufacturing differences.

Technically speaking, the CRCB-series Humphrey solenoids tend to offer increased venting, and their valves can withstand higher pressures. However, the drawback is the spool takes more time to shift, so dwell times are often higher. The Shocker's Parker K-series solenoid has lower dwell times and are easier to disassemble for cleaning, but can be less reliable due to the electronics connection. Humphrey solenoids are arguably "better made" but have a higher cost as a result. The Humphrey solenoids also offer a removeable upper circuit board to help combat the problem of Parker solenoid coil damage. Parker solenoids require you to desolder the upper board in order to remove it (see the Connection section below).

Parker K4H01 solenoids from a classic Impulse and pre-03 Shocker Sport will functionally work in a 2003+ Shocker. However, the circuit board won't attach to the top of one of these solenoids because they were designed to attach wires. While they can technically be modified, this isn't a modifiction I suggest you perform unless you have the right equipment. The solenoid terminals are very fragile and easy to damage, which generally cannot be repaired.

Solenoid/Upper Board Connection:The upper board is removable with the newer Humphrey solenoids, but NOT removable with the older Parkers. Parker solenoid terminals are soldered directly to the circuit board, which therefore cannot be removed unless it is desoldered from the solenoid terminals. I personally do not recommend doing this for any reason, unless you are absolutely forced to do so. I recommend this soldering task only for advanced technicians, since desoldering the solenoid is a very delicate operation and the coil terminals are extremely fragile.

Solenoid Manifold:The solenoid is screwed onto the body of the Shocker at the spool housing end; this is the end where airflow is exchanged between the Shocker and the solenoid. Located between the solenoid and the Shocker body is a metal plate known as the solenoid manifold, which supports and aligns a series of o-rings used to seal the air exchange. The below diagram shows the o-ring grooves and the o-rings that fit inside:

Metric o-ring diagram for Shocker/Nerve solenoid manifolds

Note: the pair of 1x3-mm o-rings are common circular o-rings which have been pushed down into the ovular groove. These o-rings will appear ovular once installed in position.
The tapered side of the manifold faces toward the front of the marker. The marker will leak if installed backwards. Also note that the frame cannot be installed if the manifold is mounted backwards.
Although the Nerve also uses a solenoid manifold, Shocker and Nerve manifolds are not interchangeable.
Solenoid "body gaskets" from Impulses and pre-2003 Shockers will not work with a 2003+ Shocker solenoid.

Solenoid Manifold Mounting:The solenoid manifold is secured onto the Shocker body using a pair of #4-40 x 1/4" button head screws, which accept a 1/16" allen wrench for removal. The solenoid itself is attached to the top of the manifold using a pair of specialty spacer screws, which will also accept a 1/16" allen for removal, however can't be purchased at a local store. The spacer screws have a tall head to help support the upper circuit board.

Solenoid "spacer screw" pair

Solenoid manifold-to-body screw pair

Note: Original 2003 model Shockers used a different style of spacer screws, which are still occasionally seen today. These screws were two screws in one; a hex head screw held the solenoid to the manifold, with a smaller socket head cap screw holding the circuit board on top. These were replaced coming into 2004 since assembly was very difficult; the updated spacer screws are significantly easier to operate and were used throughout the rest of the Shocker and Nerve lifetimes.

When reinstalling solenoid spacer screws, DO NOT overtighten them into the manifold. The threads are very fine and will easily strip out if you torque the screws too hard. Overtightening screws in the marker is never a good idea, and will be extremely easy to cause damage in this case. A stripped solenoid manifold cannot be fixed; it can only be replaced with a new one.
Severe overpressurization to the marker has been known to strip the solenoid manifold as well. This would generally be pressures of 240-psi or higher. If you overpressurize your marker and it is now leaking, this is a probable cause (please refer to the Troubleshooting page for solenoid leak information).

Aftermarket Solenoid Manifolds: Stainless Steel VersionsSome alternate manifolds are available in addition to the OEM/stock versions. The benefits of these aftermarket replacements varies depending on the specific goal you have in mind for upgrading. Some manifolds offer a performance change whereas others are simply made from stronger materials (stainless steel). In brief, manifolds made from stainless steel will offer more protection against stripping. Alternately, manifolds with adjustable bolt speed can be utilized to slow the marker's bolt speed, thereby allowing it to fire brittle-shell paint, which would otherwise be broken on the boltface or SFT breech o-ring.
Below is a list of every manifold you might find on a Shocker:

Manifolds offering stronger material:

EvolveStainless manifold

Evolve was the first company to release a stainless steel Shocker solenoid manifold in 2004. WARNING: these manifolds aren't threaded the same as all other Shocker/Nerve manifolds; they were originally shipped with a new set of hex head cap screws and are incompatible with the typical "spacer screws" used by Shockers and Nerves. Therefore you will not be able to use a secondhand Evolve manifold without the matching screws.

Evolve stainless steel manifold

New DesignzStainless manifold

Another stainless steel manifold, made by New Designz. These are the most common aftermarket manifolds for Shockers and Nerves, because NDZ accessoies were very easy to buy when Shockers were in production. The NDZ manifolds are compatible with common Shocker/Nerve spacer screws. NDZ manifolds are engraved on the body side ("SHK" or "NRV") to denote which marker they belong. The NDZ manifolds have ball-rounded flow paths which theoretically increase airflow moving through the solenoid; however there isn't a measureable performance increase from this feature (velocity is unchanged). The strong stainless steel material is the true measureable advantage of this manifold.

New Designz stainless steel manifold

Manifolds offering bolt speed control:

Smart PartsAir Vent manifold

The air vent manifold was the original adjustable-bolt-speed system and the first of its kind; it was primarilly used by SP-sponsored teams when Shockers were in production. The manifold was initially available for purchase from SP Europe only, then later available from US retailers for $50. However, Smart Parts never really advertised the benefits of the manifold, so they are fairly uncommon; few players outside of sponsored team-markers own them. Some players have an Air Vent manifold in their marker but use it just as a stock manifold, negating any possible benefits.
The Air Vent manifold is made from the same aluminum material as the stock/OEM manifolds. It uses a pair of 2-56 thread set screws to constrict exhaust, which require an extremely tiny 0.035" allen key for adjustment. These manifolds are anodized silver in color.

Smart Parts air vent manifold

SpeedsCustomAdjustable manifold

Released in 2009, these manifolds offer the same adjustable benefit as the previous Air Vent manifolds. These manifolds were also cheaper in price. They're made from aluminum and anodized black. (note: the picture may not depict a black manifold). These manifolds also use a tiny 0.035" allen key for adjustment.

SpeedsCustom adjustable manifold

Manifolds offering both stronger material and bolt speed control:

Nummech/ZDSPBSAM stainless adjustable manifold

This unique stainless manifold offers partial bolt speed adjustment ONLY when used in conjunction with a marker made from a Slug-style Nummech/ZDSPB Shocker body. Slug Shocker bodies were built with an additional air channel and adjustable set screw hole located beneath the manifold, which can control the bolt's forward speed when using a SAM manifold.
SAM manifolds can be used with any Shocker body, however most Shockers cannot take advantage of the flow restriction. The only way to achieve a stainless solenoid manifold while simultaneously offering adjustable bolt speed was to redesign the entire marker!
Shockers made from Slug bodies use a 4-40 "cone point" set screw located in the right side of the marker body; it's adjusted using a 1/16" allen key.

SAM stainless adjustable manifold rendering

Adjustable Bolt Speed Theory:Manifold adjustment is meant to purposely slow down the bolt's movement speed, thereby allowing it to act more gentle when firing brittle-shell paint (perhaps used in tournaments or special events). Adjustable manifolds accomplish this goal by constricting the bolt's exhaust airflow leading out from the solenoid. This creates an air-pillow effect that will slow the firing speed by "holding back" the bolt. Dwell time is lengthened, but single shot velocity is unchanged.

Under normal conditions, Shockers are able to cycle in the range of 30 balls-per-second when properly tuned. However, when playing under a "capped ROF" field regulation that is limited to 15-BPS or slower, the maximum firing rate of any marker being used on the field is completely irrevelant to the game at hand. When everyone is limited to the field's arbitrary ROF limit, the ability to shoot 20-BPS, 30-BPS, 40-BPS,...means nothing in a practical sense.

The above scenario describes the condition where a performance advantage can be gained using an adjustable manifold. By slowing the marker's bolt, an adjustable manifold allows you to cycle the marker more gently compared to other markers on the field, at the cost of the "unused" theoretical firing speeds. When properly adjusted, Shockers using this type of system would experience a velocity dropoff when firing above the field's ROF limit. The beauty of the system is that the marker will never exceed the legal ROF limit due to electronic caps, so no performance is noticeable.

Bolt speed adjustment is an advanced activity that requires a large amount of patience. Achieving the correct balance in mechanical settings requires you to waste at least one full tank of air, possibly more. You will need to have access to a chronograph for testing, and test fire several hopper-loads of paint in order to achieve the correct balance. In addition, adjustments are carried out while rapid-firing, so fullyautomatic or NXL mode is virtually required (the adjustment proceedure cannot be carried out with semiautomatic firing).

Most players need not bother with the advanced bolt adjustment, unless playing on the professional level or otherwise attempting to squeeze every last bit of performance from the marker. Also note that slowing the bolt is directly contrary to using a bolt with spring mod or "QEV porting", both of which are meant to increase bolt speed rather than decrease it. As with many other parts of the marker, the set of components you choose to use may depend on your specific goals. A fast-firing bolt will work nicely when trying to eliminate FSDO and reduce dwell, or achieving impractical firing speeds in a non-gameplay exhibition setting. However, you cannot combine those goals with a bolt speed dampening bolt meant to shoot brittle paint.

Overview:· The solenoid is a pneumatic valve that switches airflow within the marker, when energized by electricity from the circuit board.
· Older markers came with Parker solenoids, newer ones come with Humphrey solenoids.
· Parker solenoids are NOT removable from the circuit board. Humphrey solenoids are.
· The solenoid manifold is a mounting plate between the solenoid and the body; it houses o-rings that seal the solenoid pressures.
· The solenoid manifold is easily stripped by overtightening.